Hello,
I am just working on my diploma thesis and I have reached problem with live validation. Even if I set live validation in gmfgen file as true it does nothing. So that I have tried to follow insturctions described here, but I still get errors and exceptions. Is there any proper way to run validation after every change in diagram?

what kind of error do you get? How sophisticated is your validation? Does it make sense to run it on each change or on model save only? I think that are some questions you need to be aware before deciding for one way and solve the problems that come up.